Phased Array Ultrasonic Testing:

Basic concepts:The distinguishing feature of the phased array ultrasonic testing is the computer controlled excitation of the individual elements in a multielements probe. The excitation of these multiple piezo composite elements generates a focused ultrasonic beam, allowing the dynamic modification of the beam parameters such as angle, focal distance and focal spot size through software. To generate beam in phase by means of constructive interference, the various active elements are pulsed at slightly different times. Similarly, the echo from the desired focal point hits the various elements with a computable time shift.The echoes received by elements are time shifted before being summed together. The resulting sum in an A-scan that emphasizes the response from the focal point and attenuates from other points in the test piece.